Pancreatic lipase is a 48 kD protein present in pancreatic secretions. It has been implicated to have a crucial role in the digestion of fat in the intestinal lumen. In vitro data has also suggested that pancreatic lipase activity is important for the efficient absorption of dietary cholesterol. The aims of this research proposal are to determine the relationship between pancreatic lipase gene expression and dietary fat and cholesterol absorption. This will be achieved by generating knockout mice deficient in pancreatic lipase. Initially, mice expressing various levels of pancreatic lipase will be characterized based on their growth and overall health. Fat and cholesterol absorption studies will be performed to assess the role of pancreatic lipase in dietary lipid absorption in vivo. These results will be correlated with mRNA levels to establish the relationship between PL mRNA level and fat and cholesterol absorption efficiency in the various transgenic mice. The mice will also be fed high fat and high fat/high cholesterol diets to assess the role pancreatic lipase plays in regulating serum lipid levels. The impact of recombinant adenoviral-mediated ectopic pancreatic lipase expression in the biliary epitheliurn will be performed to determine if this would be a feasible treatment for fat malabsorption associated with pancreatic insufficiency and cystic fibrosis. These studies will provide nutritionists and clinicians with mechanistic information to design effective dietary and/or therapeutic treatment for diseases due to diet-induced hyperlipidemia or to aberrant fat digestion and transport due to pancreatic diseases.